The present invention relates to a tightening structure or a wrap closure and fit system of an article of footwear, and more particularly, a system for wrapping a foot of a shoe wearer in a loop shape and securing an article of footwear to the foot.
Generally, in use of an athletic shoe, the fit or fittability of the shoe is important to a shoe wearer especially at the heel portion of the shoe. Various techniques have been utilized to improve the fittability of the shoe at its heel portion.
For example, Japanese patent application examined publication or Kokoku No. 63-30001 discloses a shoe that has a pair of fastening members attached to the inside of the rear portion of the shoe upper in order to fasten the upper front position of a talus of a foot of a shoe wearer toward a calcaneus of the foot. Japanese utility model registration No. 3038156 shows a shoe that has a highly strengthened first belt member extending from the heel portion to the upper portion of the eyelets and a highly strengthened second belt member extending from the plantar arch portion to the instep, whereby the shoe upper is tightened.
In the methods shown in the above-mentioned Japanese publications, a certain degree of effect is achieved to improve the fittability of the shoe at the heel portion. However, in these methods, deformation of the shoe during sports and slippage of the foot inside the shoe cannot be prevented. Also, in these methods, at the time of the weight shift of the shoe wearer, sinking of the inside arch or plantar arch portion of the foot cannot be prevented either.
In general, deformation of a shoe during sports and slippage of a foot inside the shoe can be prevented by attaching a reinforcing member of high rigidity or a heel counter to a heel portion of the shoe. However, in this case, to provide the heel counter results in the increased number of shoe components and decreased productivity. Accordingly, there is provided a shoe with a reinforcing member that covers the whole heel portion and is formed integrally with the midsole so as to decrease the number of the shoe components (see Japanese patent application laying open publication or Kokai No. 5-199901). But, in this case, there arise disadvantages of the increased weight of the whole shoe and decreased ventilation of the shoe. In addition, providing a projection at the insole can prevent the inside arch from sinking at the time of the weight shift of the shoe wearer. However, in this case, the number of shoe components increases and productivity decreases.
We, inventors of the present invention have been biodynamically analyzing the stress applied to a shoe and the foot of a shoe wearer at the time of playing sports. By this analysis, we have found that it is important to provide a side wall or a supporting portion along a lateral region extending from the head of the fifth metatarsus to the calcaneus of the foot in order to prevent the foot from slipping in the lateral or transverse direction inside the shoe. We have also found that a supporting structure of the navicular is important to prevent the plantar arch portion of the foot from sinking during sports as a result of an anatomical analysis of a skeletal structure of the foot. Consequently, if these supporting elements can be made integral with an element for preventing the foot from slipping forward inside the shoe during sports, we suppose that an athletic shoe satisfying both the fittability and supportability can be achieved with a minimum of shoe components.
The present invention has been made in view of this standpoint, and its object is to provide a tightening structure or a wrap closure and fit system of an article of footwear and an athletic shoe that can improve the fittability, supportability and stability with a minimum of shoe components.
A first invention provides a tightening structure of footwear for wrapping a foot of a shoe wearer in a loop shape. The structure of the first invention includes a supporting member to support the lateral side of the foot, which extends from the position near the head of the metatarsus on the lateral side of the foot over the rear portion of the calcaneus to the medial side of the foot. The structure also includes a first fastening element of a loop shape, which is formed integrally with the terminus or the proximal end of the supporting member, and extends upwardly toward the position of the navicular on the medial side, and passes over the instep of the foot above the navicular, and returns to the lateral side of the foot and to the lateral side of the calcaneus of the supporting member.
In this case, the supporting member can prevent a transverse slippage or slippage toward the lateral side of the foot inside the footwear at the time of landing onto the ground. Moreover, by providing the first fastening element of a loop shape, an instep supporting portion of the first fastening element, which passes over the instep of the foot, can prevent the forward slippage of the foot inside the footwear on landing. Furthermore, an inside wall portion of the first fastening element, which extends upwardly toward the navicular of the foot on the medial side, supports the navicular to raise it up with the navicular wrapped or enclosed in the inside wall portion. Thus, at the time of the weight shift from the heel portion to the forefoot portion, sinking of the inside arch can be prevented, thereby preventing an excessive inclination of the foot toward the medial side and improving the heel stability.
Also, in this case, because the first fastening element is integrated with the supporting member, both the fittability and supportability of the footwear can be satisfied with a minimum of shoe components.
In addition, the term xe2x80x9cloopxe2x80x9d in the first invention means annular.
A second invention provides a similar tightening structure of footwear for wrapping the foot of a shoe wearer in a loop shape. The structure of the second invention includes a supporting member to support the lateral side of the foot, which extends from the position near the head of the metatarsus on the lateral side of the foot over the rear portion of the calcaneus to the medial side of the foot. The structure also includes a second fastening element of a loop shape, which is formed integrally with the supporting member, and extends between the medial side and the lateral side on the rear side of the base of the proximal phalanx of the foot. In this case, the supporting member can prevent a transverse slippage or slippage toward the lateral side of the foot inside the footwear at the time of landing onto the ground. Moreover, by providing the second fastening element of a loop shape, an instep supporting portion of the second fastening element, which passes over the instep of the foot, can prevent the forward slippage of the foot inside the footwear on landing.
Furthermore, in this case, because the second fastening element is integrated with the supporting member, both the fittability and supportability of the footwear can be satisfied with a minimum of shoe components.
In addition, the term xe2x80x9cloopxe2x80x9d in the second invention is used with the meaning of a slightly curved circular arc.
The upper end of each of the supporting members in the first and second inventions is preferably placed at the position in the vicinity of xe2x80x98a swell linexe2x80x99 around the outer circumference of the foot of the shoe wearer, that is, a line forming the contour of a horizontally projected plan of the foot, or in other words, a line connecting the most projected or protruded portions around the outer circumference of the foot. More preferably, the upper end of the height of the supporting member is slightly beyond this swell line.
The first and second fastening elements each may be formed of medial fastening elements provided on the medial side, lateral fastening elements provided on the lateral side, and joining or securing parts that join these medial and lateral fastening elements. The termini or distal ends of the medial fastening elements are preferably disposed on the lateral side beyond a center line of the shoe. This is for wrapping or enclosing the wider areas of the lateral navicular position to prevent a local excessive pressure, and for preventing each of the fastening elements of a left and right shoe from interfering with each other.
An athletic shoe is a favorable example of footwear to which the first and second inventions are applied, and in the athletic shoe, at least portions of the medial and lateral fastening elements may be provided outside or inside the shoe upper, or in the shoe upper. Also, each of the proximal ends of the medial and lateral fastening elements of the shoe may be anchored to the shoe upper or the heel portion of a midsole, and each of the distal ends of the medial and lateral fastening elements may be connected to the joining part, and each of the intermediate portions of the medial and lateral fastening elements may be disconnected from the shoe upper. Additionally, in the athletic shoe to which the present invention is applied, a corrugated sheet having a corrugation may be provided at least at the heel portion of the midsole formed of a soft elastic material.